Which is the hardest tissue of the body?

• A. Dentin
• B. Cementum
• C. Enamel
• D. Bone

Answer: (C)

Hardness in dental tissues is determined by how densely mineralized the tissue is and how the mineral crystals are arranged. Enamel has an extremely high mineral content and a highly organized structure of tightly packed hydroxyapatite crystals—the enamel rods and prisms—so it resists indentation and wear far more than the other tissues. Enamel is about 96% inorganic material, whereas dentin and cementum are around 70% inorganic and bone is even less. This intense mineralization, along with the orderly crystal arrangement, gives enamel its exceptional hardness. It’s also worth noting that enamel is acellular and cannot remodel once formed, unlike dentin and bone, which can respond to damage. All these factors together make enamel the hardest tissue in the body.